Department of Orthodontics, The University of Texas/Houston Dental Branch, Houston, TX, USA.
Am J Orthod Dentofacial Orthop. 2011 Mar;139(3):356-61. doi: 10.1016/j.ajodo.2009.05.036.
Our aims were to evaluate long-term maxillary arch width changes in orthodontic patients treated with and without premolar extractions and to provide a potential link to the buccal-corridor ratios.
Dental casts of 34 extraction and 32 nonextraction orthodontic patients with Class I malocclusions were digitized and evaluated before treatment (T1), at posttreatment (T2), and at postretention (T3). The mean postretention times for the extraction and the nonextraction groups were 5 years 2 months and 4 years 10 months, respectively. Specific arch width measurements were made on the anatomic y-axis of the casts between the most labial aspects of the anatomic dental arch immediately distal to the incisive papilla, the farthest point posteriorly of the conjunction of the third lateral and medial rugae on the midpalatal raphe and at an individually constant distance from the incisive papilla. Arch width changes were calculated and compared statistically to determine whether the dental arches were narrower after extraction treatment and at postretention.
All maxillary arch width measurements remained virtually stable after extraction therapy and at the postretention follow-up. Significant increases were recorded for all maxillary arch width measurements in the nonextraction group after treatment (mean changes, 1.37-2.05 mm). Posterior arch width measurements decreased significantly between T2 and T3 (mean change, 0.5 mm). Mean changes between T1 and T2 were significant between the 2 groups for all measurements (P <0.05). Only the mean change in posterior arch width was significant between the 2 groups in the postretention period (P <0.05).
Extraction treatment did not result in narrower maxillary dental arches, whereas nonextraction treatment slightly expanded the dental arch.
我们的目的是评估接受和不接受前磨牙拔牙的正畸患者的上颌弓宽度的长期变化，并为颊廊比提供潜在的联系。
对 34 例拔牙和 32 例非拔牙正畸患者的牙模进行数字化处理，在治疗前（T1）、治疗后（T2）和保持后（T3）进行评估。拔牙组和非拔牙组的平均保持时间分别为 5 年 2 个月和 4 年 10 个月。在牙模的解剖 Y 轴上，在切牙乳头最唇侧的解剖牙弓之间，在中切牙切迹处的第三外侧和内侧皱襞的结合部的最远处，以及距切牙乳头的个体恒定距离处，进行特定的弓宽测量。计算弓宽变化并进行统计学比较，以确定拔牙治疗后和保持后牙弓是否变窄。
所有上颌弓宽度测量值在拔牙治疗后和保持后随访期间基本保持稳定。非拔牙组治疗后所有上颌弓宽度测量值均显著增加（平均变化 1.37-2.05 毫米）。治疗后 T2 至 T3 时，后弓宽度测量值显著减小（平均变化 0.5 毫米）。两组之间 T1 至 T2 之间的所有测量值的平均变化均有统计学意义（P<0.05）。仅在保持期间，两组之间的后弓宽度的平均变化具有统计学意义（P<0.05）。
拔牙治疗并未导致上颌牙弓变窄，而非拔牙治疗则略微扩大了牙弓。
